The present invention relates to Internet Protocol (IP) address management on networks and more specifically to Dynamic Host Configuration Protocol (DHCP) management.
The Dynamic Host Configuration Protocol (DHCP) [8] enables devices to attach to networks without manual configuration. It does, however, require manual configuration of access policies at the DHCP servers. One of the most critical parameter of the DHCP server configuration is the lease duration, indicating how long a device can use an IP address. Setting up proper DCHP lease values has been an art rather than a science. Long lease times can lead to exhaustion of the network address pool assigned for DHCP, while short ones can result in increased broadcast traffic and unnecessary activation of wireless interfaces by power limited devices.
There have been few studies on the DHCP lease times [7, 10], both of which were done before the onslaught of smartphones in local area networks. Smartphones present a challenge in correctly configuring DHCP leases. A single device may acquire multiple IP addresses during a day due to its continuous attachment, in either asleep or active mode, with the campus-wide wireless networks. For example, as a student moves from one side of the campus to another, her devices can re-associate with various campus subnets, acquiring a different address each time. In this scenario, setting DHCP lease times even as low as one hour may not necessarily be enough to reduce network address utilization.